We’ve already brought you the 25 most insane concept yachts on Earth. Unfortunately, however, you won’t see too many of those on the water…they’re just concepts. The yachts you are about to see on the other hand, have nothing conceptual about them. They are the largest, most lavish toys on the planet and not surprisingly they belong to some of the world’s wealthiest individuals. These are the 25 most expensive yachts ever built. 1. History…